Preheat oven to 175°C - 350°F - Gas Mark 4.
In a medium bowl, mix the flours, cocoa powder, coconut sugar, salt and baking soda.
In a large bowl, whisk together the coconut oil, coconut milk, eggs, vanilla extract and honey.
Carefully and using a rubber spatula, mix in the dry ingredients into the wet ingredients. Be careful not to over mix.
Pour the batter into an oiled cake tin.
Bake for 45 minutes or until firm to touch and a skewer inserted in the center comes out clean.